The
genus Pestalotiopsis is second most
important fungal pathogen causing grey blight disease in tea plant
(Camellia sinensis). Due to grey blight disease, total tea crop loss is
estimated to be 17% in southern India.
In the present study, 42 Pestalotiopsis isolates were collected from five different
regions in southern India.
Among them, 22 isolates showed diverse morphological characters like colour,
size and length of conidia and virulence. Genetic diversity was studied for
these 22 isolates using two molecular marker systems (RAPD and ISSR). In RAPD,
a total of 255 loci were generated and all were polymorphic in nature and the
band size ranged from 0.2 to 3.0 kb. In ISSR, 194 amplified loci were observed
and all were polymorphic as like RAPD and the band size ranged from 0.25 to 3.2
kb. Using Jaccard’s similarity coefficient matrix, highest similarity of 95.9%
and 92.6% was observed between AP-8 and AP-9 isolates in both RAPD and ISSR
markers, respectively. Lowest similarity was observed between AP-14 and NP-5
(8.8%) in RAPD matrix but in ISSR matrix lowest similarity (18.5%) was between
AP-14 and EN-5. The UPGMA clustering of both methods was comparable. The
results indicate that, within southern India, the diversity of Pestalotiopsis was high both morphologically and genetically